Re: [PATCH v3 1/6] media: v4l2_ctrl: Add region of interest rectangle control

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, May 19, 2022 at 10:14:05AM +0200, Hans Verkuil wrote:
> On 5/18/22 08:24, Yunke Cao wrote:
> > Including:
> > 1. Add a control ID.
> > 2. Add p_rect to struct v4l2_ext_control with basic support in
> >    v4l2-ctrls.
> > 
> > Signed-off-by: Yunke Cao <yunkec@google.com>
> > ---
> > Changelog since v2:
> > - Better documentation.
> > 
> >  .../media/v4l/ext-ctrls-camera.rst            | 10 ++++++++++
> >  .../media/v4l/vidioc-g-ext-ctrls.rst          |  4 ++++
> >  .../media/videodev2.h.rst.exceptions          |  1 +
> >  drivers/media/v4l2-core/v4l2-ctrls-core.c     | 20 +++++++++++++++++++
> >  drivers/media/v4l2-core/v4l2-ctrls-defs.c     |  4 ++++
> >  include/media/v4l2-ctrls.h                    |  2 ++
> >  include/uapi/linux/v4l2-controls.h            |  2 ++
> >  include/uapi/linux/videodev2.h                |  2 ++
> >  8 files changed, 45 insertions(+)
> > 
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> > index 4c5061aa9cd4..c988a72b97b2 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> > @@ -661,3 +661,13 @@ enum v4l2_scene_mode -
> >  .. [#f1]
> >     This control may be changed to a menu control in the future, if more
> >     options are required.
> > +
> > +``V4L2_CID_REGION_OF_INTEREST_RECT (struct)``
> > +   This control determines the region of interest. Region of interest is an
> > +   rectangular area represented by a struct v4l2_rect. The rectangle is in
> > +   pixel units and global coordinates. Use ``V4L2_CTRL_WHICH_MIN_VAL`` and
> > +   ``V4L2_CTRL_WHICH_MAX_VAL`` to query the range of coordinates.
> 
> Hmm, what does MIN and MAX mean in terms of a rectangle? It makes sense for
> the width and height, but how is that interpreted for top and left?
> 
> Are these the minimum and maximum values each field of the struct can have?
> So if the image is, say, 640x480, then the minimum value for a rectangle might
> be 1x1@0x0, and the maximum 640x480@639x479. So in that case these are not real
> rectangles, but they give the range for each field of the struct.
> 
> An alternative would be to see this as the min and max rectangle size and keep
> the top/left values at 0.
> 
> To be honest, I'm not sure which one I would prefer.

I'm also really worried fo the interactions between this control and
selection rectangles. The uvcvideo driver won't need to care, but this
is a generic control, so we need to define it clearly.

To be honest, given how specific to UVC this is, I'd create
device-specific controls. I don't foresee any other driver being able to
make use of V4L2_CID_REGION_OF_INTEREST_RECT and
V4L2_CID_REGION_OF_INTEREST_AUTO.

> > +
> > +   Setting a region of interest allows the camera to optimize the capture for
> > +   the region. The value of ``V4L2_CID_REGION_OF_INTEREST_AUTO`` control
> > +   determines the detailed behavior.
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > index 29971a45a2d4..f4e205ead0a2 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > @@ -189,6 +189,10 @@ still cause this situation.
> >        - ``p_area``
> >        - A pointer to a struct :c:type:`v4l2_area`. Valid if this control is
> >          of type ``V4L2_CTRL_TYPE_AREA``.
> > +    * - struct :c:type:`v4l2_rect` *
> > +      - ``p_area``
> > +      - A pointer to a struct :c:type:`v4l2_rect`. Valid if this control is
> > +        of type ``V4L2_CTRL_TYPE_RECT``.
> >      * - struct :c:type:`v4l2_ctrl_h264_sps` *
> >        - ``p_h264_sps``
> >        - A pointer to a struct :c:type:`v4l2_ctrl_h264_sps`. Valid if this control is
> > diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > index 9cbb7a0c354a..7b423475281d 100644
> > --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > @@ -147,6 +147,7 @@ replace symbol V4L2_CTRL_TYPE_HEVC_SPS :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_HEVC_PPS :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_AREA :c:type:`v4l2_ctrl_type`
> > +replace symbol V4L2_CTRL_TYPE_RECT :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_FWHT_PARAMS :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_VP8_FRAME :c:type:`v4l2_ctrl_type`
> >  replace symbol V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR :c:type:`v4l2_ctrl_type`
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > index 8968cec8454e..dcde405c2713 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > @@ -84,6 +84,11 @@ static bool std_equal(const struct v4l2_ctrl *ctrl, u32 idx,
> >  		return ptr1.p_u16[idx] == ptr2.p_u16[idx];
> >  	case V4L2_CTRL_TYPE_U32:
> >  		return ptr1.p_u32[idx] == ptr2.p_u32[idx];
> > +	case V4L2_CTRL_TYPE_RECT:
> > +		return ptr1.p_rect->top == ptr2.p_rect->top &&
> > +		       ptr1.p_rect->left == ptr2.p_rect->left &&
> > +		       ptr1.p_rect->height == ptr2.p_rect->height &&
> > +		       ptr1.p_rect->width == ptr2.p_rect->width;
> >  	default:
> >  		if (ctrl->is_int)
> >  			return ptr1.p_s32[idx] == ptr2.p_s32[idx];
> > @@ -307,6 +312,11 @@ static void std_log(const struct v4l2_ctrl *ctrl)
> >  	case V4L2_CTRL_TYPE_VP9_FRAME:
> >  		pr_cont("VP9_FRAME");
> >  		break;
> > +	case V4L2_CTRL_TYPE_RECT:
> > +		pr_cont("l: %d, t: %d, w: %u, h: %u",
> > +			ptr.p_rect->left, ptr.p_rect->top,
> > +			ptr.p_rect->width, ptr.p_rect->height);
> > +		break;
> >  	default:
> >  		pr_cont("unknown type %d", ctrl->type);
> >  		break;
> > @@ -525,6 +535,7 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> >  	struct v4l2_ctrl_hdr10_mastering_display *p_hdr10_mastering;
> >  	struct v4l2_ctrl_hevc_decode_params *p_hevc_decode_params;
> >  	struct v4l2_area *area;
> > +	struct v4l2_rect *rect;
> >  	void *p = ptr.p + idx * ctrl->elem_size;
> >  	unsigned int i;
> >  
> > @@ -888,6 +899,12 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> >  			return -EINVAL;
> >  		break;
> >  
> > +	case V4L2_CTRL_TYPE_RECT:
> > +		rect = p;
> > +		if (!rect->width || !rect->height)
> > +			return -EINVAL;
> > +		break;
> > +
> >  	default:
> >  		return -EINVAL;
> >  	}
> > @@ -1456,6 +1473,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >  	case V4L2_CTRL_TYPE_AREA:
> >  		elem_size = sizeof(struct v4l2_area);
> >  		break;
> > +	case V4L2_CTRL_TYPE_RECT:
> > +		elem_size = sizeof(struct v4l2_rect);
> > +		break;
> >  	default:
> >  		if (type < V4L2_CTRL_COMPOUND_TYPES)
> >  			elem_size = sizeof(s32);
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > index 54ca4e6b820b..95f39a2d2ad2 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > @@ -1042,6 +1042,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >  	case V4L2_CID_UNIT_CELL_SIZE:		return "Unit Cell Size";
> >  	case V4L2_CID_CAMERA_ORIENTATION:	return "Camera Orientation";
> >  	case V4L2_CID_CAMERA_SENSOR_ROTATION:	return "Camera Sensor Rotation";
> > +	case V4L2_CID_REGION_OF_INTEREST_RECT:  return "Region Of Interest Rectangle";
> >  
> >  	/* FM Radio Modulator controls */
> >  	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
> > @@ -1524,6 +1525,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >  	case V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY:
> >  		*type = V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY;
> >  		break;
> > +	case V4L2_CID_REGION_OF_INTEREST_RECT:
> > +		*type = V4L2_CTRL_TYPE_RECT;
> > +		break;
> >  	default:
> >  		*type = V4L2_CTRL_TYPE_INTEGER;
> >  		break;
> > diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> > index b3ce438f1329..919e104de50b 100644
> > --- a/include/media/v4l2-ctrls.h
> > +++ b/include/media/v4l2-ctrls.h
> > @@ -58,6 +58,7 @@ struct video_device;
> >   * @p_hdr10_cll:		Pointer to an HDR10 Content Light Level structure.
> >   * @p_hdr10_mastering:		Pointer to an HDR10 Mastering Display structure.
> >   * @p_area:			Pointer to an area.
> > + * @p_rect:			Pointer to a rectangle.
> >   * @p:				Pointer to a compound value.
> >   * @p_const:			Pointer to a constant compound value.
> >   */
> > @@ -87,6 +88,7 @@ union v4l2_ctrl_ptr {
> >  	struct v4l2_ctrl_hdr10_cll_info *p_hdr10_cll;
> >  	struct v4l2_ctrl_hdr10_mastering_display *p_hdr10_mastering;
> >  	struct v4l2_area *p_area;
> > +	struct v4l2_rect *p_rect;
> >  	void *p;
> >  	const void *p_const;
> >  };
> > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> > index bb40129446d4..499fcddb6254 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -1008,6 +1008,8 @@ enum v4l2_auto_focus_range {
> >  
> >  #define V4L2_CID_CAMERA_SENSOR_ROTATION		(V4L2_CID_CAMERA_CLASS_BASE+35)
> >  
> > +#define V4L2_CID_REGION_OF_INTEREST_RECT	(V4L2_CID_CAMERA_CLASS_BASE+36)
> > +
> >  /* FM Modulator class control IDs */
> >  
> >  #define V4L2_CID_FM_TX_CLASS_BASE		(V4L2_CTRL_CLASS_FM_TX | 0x900)
> > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > index 3768a0a80830..b712412cf763 100644
> > --- a/include/uapi/linux/videodev2.h
> > +++ b/include/uapi/linux/videodev2.h
> > @@ -1751,6 +1751,7 @@ struct v4l2_ext_control {
> >  		__u16 __user *p_u16;
> >  		__u32 __user *p_u32;
> >  		struct v4l2_area __user *p_area;
> > +		struct v4l2_rect __user *p_rect;
> >  		struct v4l2_ctrl_h264_sps __user *p_h264_sps;
> >  		struct v4l2_ctrl_h264_pps *p_h264_pps;
> >  		struct v4l2_ctrl_h264_scaling_matrix __user *p_h264_scaling_matrix;
> > @@ -1810,6 +1811,7 @@ enum v4l2_ctrl_type {
> >  	V4L2_CTRL_TYPE_U16	     = 0x0101,
> >  	V4L2_CTRL_TYPE_U32	     = 0x0102,
> >  	V4L2_CTRL_TYPE_AREA          = 0x0106,
> > +	V4L2_CTRL_TYPE_RECT	     = 0x0107,
> >  
> >  	V4L2_CTRL_TYPE_HDR10_CLL_INFO		= 0x0110,
> >  	V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY	= 0x0111,

-- 
Regards,

Laurent Pinchart